The invention relates to a color electrophotographic apparatus, and relates more particularly to a color electrophotographic apparatus in which a color image is transferred after the color image was superimposed on a photoreceptor drum.
Up to the present, the following electrophotographic apparatuses have been widely known: a color electrostatic copier in which color images can be copied by the electrophotographic process; and a color printer in which color images can be recorded according to color image signals which are transmitted from the outside. Among these apparatuses, there is a color image recording apparatus which is characterized in that: the color images (yellow, magenta, cyan, black and the like) are superimposed on a photoreceptor; and then the superimposed color images are recorded on a recording paper being pressed by a transfer belt. The developer which remains on the photoreceptor drum is removed by the cleaning device (a blade or a brush). As explained above, in this type of apparatuses, the color images are developed at each color and superimposed. Consequently, the transfer belt and the cleaning device must be separated from the photoreceptor drum until the development of all color images is over. Accordingly, in the case of the conventional electrophotographic color apparatus, the separation means in which a magnetic clutch and a cam are combined or in which a solenoid, a spring clutch and a cam are combined, are provided to each of the transfer means and the cleaning means, and the transfer means and the cleaning means are separated from the photoreceptor by each separation means. Accordingly, the following problems exist in the conventional apparatus: as two sets of separation mean must be provided to the apparatus, it results in increased number of parts and increased cost, and the chance of a mechanical trouble is large; and the timing difference of the motion between the transfer means and the cleaning means tends to become incorrect.
The present invention has been achieved to solve the problems described above. The object of the present invention is to provide a color electrophotographic apparatus which is characterized in that: the transfer means and the cleaning means are attached to and separated from the photoreceptor drum by almost common separation means; accordingly, the number of parts can be decreased; as a result, the cost of the apparatus can be reduced and the chance of a mechanical trouble is small; and the timing of the motion of the transfer means is scarcely deviated from that of the cleaning means.
The above-described object can be attained by the color electrophotographic apparatus of the present invention in which a color image is formed on the photoreceptor by repeatedly forming toner images of different colors and superimposing them, and after that the color toner image is directly or indirectly transferred onto a transfer paper and fixed, and which is characterized in that: the transfer means and the cleaning means installed around the photoreceptor drum can be attached to and removed from the photoreceptor drum by a cam which can be rotated around the shaft of the photoreceptor drum.
In the color photoelectric apparatus of the present invention, the transfer means and the cleaning means can be attached to and removed from the surface of the photoreceptor drum driven by a pair of cams. These cams are integrally formed, and are driven by a driver to rotate around the rotating axis of the photoreceptor drum but with an independent rotating speed. Accordingly, the number of parts can be reduced, which results in the decrease in the cost and the mechanical trouble, and furthermore the following effect can be obtained: when the transfer mean and the cleaning means are attached to and removed from the photoreceptor drum, the timing of the motion of the transfer means is not deviated from that of the cleaning means.